Hard drive media are manufactured by sputtering thin films of magnetic material on disks. The magnetic material allows data to be stored on the media and read from the media using a magnetic read/write head. Hard drive media can be either single-sided, where magnetic material is sputtered on a single side of each disk, or double-sided, where magnetic material is sputtered on both sides of each disk.
Typically, disks are manufactured and prepared for sputtering on a manufacturing line separate from the manufacturing line used to sputter the magnetic material. The disks are transported from one manufacturing line to the next using a shipping cassette designed to hold and protect multiple disks during transport. Once the shipping cassette arrives at the sputtering manufacturing line, the disks are removed from the shipping cassette and placed in a processing cassette designed to carry the disks through the sputtering manufacturing line. The process of exchanging the cassettes carrying disks as they transition from one manufacturing line to the next can create a bottleneck that slows the overall throughput of the manufacturing process.